Sodium hypochlorite or bleach is a powerful disinfecting agent and is, therefore, preferred for use in general purpose cleaning compositions. Preparing sodium hypochlorite containing compositions for general purpose cleaning utilities, it is preferred to incorporate one or more surfactants to improve cleaning performance. It is also preferred to select the surfactant system such that it increases the viscosity of the resultant composition in order to improve application of the composition onto the surfaces being cleaned. This is especially true when the composition is employed as a cleaner for vertical tile walls and bathroom fixtures. It would also be beneficial to incorporate in the composition an organic cleaning vehicle or solvent to assist in the removal of certain types of soil deposits.
Hypochlorites are strong oxidizing agents and are, therefore, incompatible with many surfactants, as well as being generally incompatible with organic solvents. Incompatibility may be manifest by reaction of one or more actives with the hypochlorite, or by physical instability, especially where the bleach composition has been thickened. In the former case, the reaction reduces the level of the active constituents, and the composition is not effective to provide its cleaning function. In some instances unwanted reaction products may further decrease performance. Physical instability, that is, where the composition separates into two or more phases over time, detracts from ease of use by the consumer; may be difficult to reconstitute to form a homogeneous mixture, and could, if used, leave on the surface to be cleaned an undesirable film of active constituents that have been concentrated within one of the phases.
Applicants have found that certain tertiary alcohols may be included in effective concentration levels in alkali metal hypochlorite-containing compositions, to provide enhanced cleaning performance, which compositions are chemically and physically stable.
U.S. Pat. No. 4,623,476 to Nayar, et al., discloses stable suspensions of pigments in aqueous hypochlorite bleach compositions, the Nayar, et al., compositions comprising from about 3 to 10% sodium hypochlorite; from about 0.01 to 0.3% of selected dyes; from 0.025 to 0.2% of optical brightener 4,4'-bis(4-phenyl-2H-1,2,3-triazol-2-yl)-2,2'-stilbenedisulfonic acid or any one of its functional equivalent derivative salts; from about 0.05 to 2% of stated alkyaryl sulfonate surfactants; and at least 80% water.
Optionally, the Nayar, et al., compositions may include from about 0.1 to about 0.5% of a bleach stable organic oil disclosed at column 5, line 26 bridging to column 7, line 7, including C.sub.6 -C.sub.20 tertiary alcohols of the formula R.sub.11 R.sub.12 R.sub.13 COH wherein R.sub.11 is a C.sub.3 -C.sub.17 saturated akyl, and R.sub.12 and R.sub.13 are C.sub.1 -C.sub.12 saturated acyclic alkyls.
The organic oil, when used in the Nayar, et al., composition, is admixed with the pigment, brightener, or surfactant solution prior to the addition of aqueous hypochlorite. The organic oil is included to increase the duration of pigment suspension in the composition, as well as to provide a fragrance thereto.
Thickened alkali metal hypochlorite compositions are known in the prior art. Thus, U.S. Pat. No. 4,388,204 to Dimond, et al., discloses thickened aqueous metal hypochlorite compositions wherein the thickening additive is composed of at least one of each of the following class of anionic surfactants: (a) alkali metal sulfate salts of ethoxylated aliphatic alcohols; (b) alkali metal salts of N-alkyl, N-acyl amino acids, and (c) alkali metal salts of alkyl sulfates. The Dimond, et al., compositions are intended primarily for use to unclog clogged drains, but may also be used as a general purpose cleaning composition.
U.S. Pat. No. 4,282,109 to Citrone, et al., discloses a thickened bleach composition including an aqueous solution of alkali metal hypochlorite and a thickening amount of a surfactant comprising (a) an amine oxide of the formula R.sup.1 R.sup.2 R.sup.2 N.fwdarw.O wherein R.sup.1 is an optionally branched chain alkyl group containing 10 to 18 carbon atoms and R.sup.2 is a lower alkyl group containing up to 3 carbon atoms, and (b) an alkali metal alkyl sulfate of the formula R.sup.3 --O--SO.sub.3 M wherein R.sup.3 is an optionally branched chain alkyl group containing 8 to 12 carbon atoms and M is lithium, sodium, or potassium, the ratio of the amine oxide to the alkali metal alkyl sulfate being not less than 3:4 and preferably greater than 13:8.
The thickened liquid bleach composition of Schilp, U.S. Pat. No. 4,337,163, incorporates as the thickening system a tertiary amine oxide and a fatty acid soap, and further contains an alkali metal orthophosphate buffer system to provide a pH of 10-12.5. U.S. Pat. No. 3,929,661 to Nakagawa, et al., discloses sodium hypochlorite compositions containing a surfactant of the formula R.sub.1 R.sub.2 R.sub.3 CCH.sub.2 OX, wherein R.sub.1, R.sub.2, and R.sub.3, which can be the same or different, are alkyls of 1 to 18 carbons atoms, the sum of the carbon atoms being from 10 to 20; X is --SO.sub.3 M, --CH.sub.2 COOM, --CH.sub.2 CH.sub.2 COOM, --(CH.sub.2 CH.sub.2 O).sub.n SO.sub.3 M or --(CH.sub.2 CH.sub.2 O).sub.n COOM, n being an integer of 1 to 40, and M is an alkali metal. In U.S. Pat. No. 4,057,505 to Nakagawa, et al., the surfactant is of the formula R.sub.1 R.sub.2 CHCH.sub.2 OSO.sub.3 M, wherein R.sub.1 and R.sub.2 are alkyls having 1 to 13 carbon atoms, the total number of carbon atoms being from 8 to 14, and M is lithium, sodium, or potassium. Choy, et al., U.S. Pat. No. 4,599,186, discloses thickened aqueous abrasive scouring cleaners wherein bleach-stable amine oxide surfactants may be incorporated. Other suitable surfactants includable in the Choy compositions are betaines, imidazolines, and certain quaternary phosphonium and tertiary sulfonium compounds. Similarly, U.S. Pat. No. 4,585,570 to Nelson discloses the incorporation of an amine oxide as a thickening component. See also U.S. Pat. Nos. 4,438,016 to Kiewert, et al., and 4,229,313 to Joy; GB No. 2,003,522A to Joy, and Japan No. 93,799.
Thickened bleach compositions are also disclosed in GB No. 1,466,560, the composition containing an alkali metal sarcosinate or tauride surfactant and another surfactant comprising (i) an alkali metal soap; (ii) a quaternary ammonium compound, (iii) an amine oxide, (iv) a betaine, or (v) an alkanolamide. See also U.S. Pat. Nos. 3,684,722 to Hynam, et al., and 4,588,514 to Jones, et al.
U.S. Pat. No. 4,461,652 to Richmond discloses a barnacle-removing process and product, the process comprising the steps of spraying the barnacled surface with a mixture comprising a hydrocarbon liquid oil; a surfactant; alcohol, a metal hypochlorite; and an alkyl, dialkyl benzel ammonium salt for about 20 minutes, the barnacles then being removed by power spraying with water. Any alcohol having a boiling point between 60.degree. and 200.degree. C. may be substituted for the preferred isopropyl alcohol.
Disadvantageously, primary and secondary alcohols are unstable in the compositions of the present invention, which require a suitable shelf life of at least about three months.
Accordingly, it is an object of the present invention to provide shelf stable aqueous hypochlorite compositions containing a tertiary alcohol and a surfactant or surfactant blend.
The primary objective of the present invention is to provide an alklai metal hypochlorite composition containing, to enhance cleaning performance, an organic solvent component which is a tertiary alcohol.
A further objective of the present invention is to provide a phase stable hypochlorite cleaning composition having a viscosity of at least about 10 centipoise, preferably from about 15 to about 75 centipoise.
These and other objects and advantages of the present invention are described in the detailed description of the invention, a summary of which follows.